1. Field of the Present Inventive Concept
The present inventive concept relates to a nitride-based semiconductor device and a method of manufacturing the nitride-based semiconductor device, and more particularly, to a nitride-based semiconductor device and a method of manufacturing the nitride-based semiconductor device that improves surface roughness of an aluminum gallium nitride (AlGaN) layer and that reduces leakage current.
2. Description of the Related Art
As information communication technologies have been considerably developed globally, communication technologies for high-speed and large-capacity signal communication have been rapidly developed. In particular, due to an increase in demands for personal mobile phones, satellite communication, military radar, broadcasting communication, communication relay, and the like in wireless communication technologies, demands for a high-speed and a high-power electronic device for high-speed information communication systems of microwave and millimeter-wave bands have increased. Consequently, a large number of research on a power device used in a high-power electronic device is being conducted to reduce energy loss.
In particular, since a gallium nitride (GaN)-based nitride semiconductor has advantageous properties, such as a high energy gap, a high thermal stability, a high chemical stability, a high electronic saturation velocity of about 3×107 centimeters per second (cm/sec), and the like, the GaN-based nitride semiconductor may be readily utilized as an optical device, and a high-frequency and high-power electronic device. Accordingly, researches on the GaN-based nitride semiconductor are being actively conducted all over the world.
An electronic device based on the GaN-based nitride semiconductor may have various advantages, such as a high breakdown field of about 3×106 volts per centimeter (V/cm), a maximum current density, a stable high temperature operation, a high thermal conductivity, and the like. A heterostructure field effect transistor (HFET) formed from a heterojunction of aluminum gallium nitride (AlGaN) and GaN has a high band-discontinuity at a junction interface, whereby a high-density of electrons may be freed at the interface and thus, an electron mobility may increase. Accordingly, the HFET may be applicable as the high-power device.
However, a structure of an AlGaN/GaN HFET with a high electron mobility may have a disadvantage in that leakage current flowing along a surface may decrease a device property, due to an unstable AlGaN surface.